Hydraulic grommet tool



Nov. 1, 1955 F. J. soMEs, JR 2,722,335

HYDRAULIC GROMMET TOOL Filed 001. 21, 1954 2 sheets-sheet 1 uw, ffl! IN V EN TOR. X MQYMSQ e,

u ,QS m1 A T raRNEYJ Nov. 1, 1955 F. J. soMEs, JR

HYDRAULIC GROMMET TOOL 2 Sheets-Sheet 2 Filed Oct. 21, 1954 INVENTOR. 'XM M `\s\ AT ram/Ens United States Patent Utilice 2,722,335 Patented Nov. 1, 1955 HYDRAULIC GRoMMET TooL Fred J. Somes, Jr., St. Clair Shores, Mich., assignor to National Electric Products Corporation, Pittsburgh, Pa., a corporation of Delaware Application October 21, 1954, Serial N o. 463,785

Claims. (Cl. 218-42) This invention relates to power-operated grommet tools such as are used for clamping the grommets that hold electric header ducts to the top walls of cellular ilooring sections, and for similar purposes. Such grommets are of large size and require so much pressure for clamping them that hand-operated tools are tedious to operate and consume so much time that they add substantially to the cost of the building project.

It is an object of this invention to provide an improved tool for setting grommets, particularly large grommets, and to provide a tool which is power-operated. Another object is to provide a hydraulically operated grommet tool which is simple and rugged in construction and which operates quietly and rapidly.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.l

In the drawing, forming a part hereof, in which like reference characters indicate correspondng parts in all the views;

Figure 1 is a side elevation of a grommet tool embodying this invention;

Figure 2 is a sectional view taken on the line 2 2 of Figure 1;

Figures 3 and 4 are transverse sectional views taken on the lines 3 3 and 4 4, respectively, of Figure l;

Figure 5 is a plan view of an auxiliary clamping plate that is used with the lower clamping plate of the tool;

Figure 6 is a sectional view taken on the line 6 6 of Figure 5 Figure 7 is a plan View of the lower clamping plate of the tool;

Figure 8 is a sectional View taken on the line 8 8 of Figure 7;

Figure 9 is a bottom plan view of the upper clamping plate of the grommet tool;

Figure 10 is a sectional view taken on the line 10 10 of Figure 9; and

Figure 11 is a diagrammatic view showing the entire assembly of the grommet tool with its pump and valve means for controlling the flow of working uid to and from the cylinder of the tool.

The grommet tool includes a lower clamping plate 10 and an upper clamping Vplate 11. The confronting faces of these clamping plates 10 and 11 are shaped to form and set a grommet in accordance with conventional practice. The lower clamping plate has an auxiliary clampnig plate 12 which ills in a portion of the circumference of the lower clamping face, as will be more fully explained in connection with Figures 5 and 8. For the presentnit is sucient to understand that the clamping plate 10 and auxiliary plate 12 are movable into positions to reduce the width of the composite clamping element which these plates 10 and 12 provide. This reduced width is necessary to permit the lower clamping plate to pass through an opening of reduced diameter and'into which the grommet is to be set.

The lower clamping plate 10 has a hub 14 through which a spindle 16 extends; and the hub 14 is secured to the spindle 16 by welding 17. v

The upper clamping plate 11 ts over the lower end of a sleeve 20 and is secured against displacement on the sleeve by a set screw 21. A bushing 23 surrounds the spindle 16, and the sleeve 20 slides longitudinally on this bushing 23. In order to prevent rotation of the sleeve 20 on the bushing 23, there is a keyway 25 in the bushing, and the inner end of the set screw 21 serves as a key in the construction illustrated. The bushing 23 ts tightly over the spindle 16 with a press t.

The grommet tool has a hollow body portion 30 into which both the spindle 16 and the sleeve 20 extend. In the construction illustrated, the spindle 16 extends throughout the entire length of the hollow body portion 30 and through a bearing 32 in an end wall of the body portion 30. There is a cylinder 34 at the upper end of the body portion 30. This cylinder is shown as a different part from the body portion but connected thereto by threads 36. The lower end of the cylinder 34 abuts against a shoulder 38 on the body portion 30 when the cylinder is screwed down tight.

The end wall of the body portion 30 closes the lower end of the cylinder, and the spindle 16 serves as a piston rod for a piston 40 located within the cylinder 34.

This piston 40 is secured to the piston rod or spindle 16 by a nut 42; and the piston has packing comprising an O-ring 44 located in a ring groove of the piston. There is other packing 46 in ring grooves in the bearing 32 in which the piston rod or spindle 16 moves longitudinally when the grommet tool is operated.

Working uid is supplied to the cylinder 34 through a port 50 in the wall of the cylinder 34 below the piston 40. There is a circumferential groove 52 provided in the upper end of the outside surface of the body portion 30 for admitting working iluid into the cylinder 34 at a location which can not be covered by the piston 40. In the construction illustrated, there is only one port 50 in the cylinder and a fitting 55 connects the port 50 with conduits through which working fluid ows either to or from the cylinder 34 in accordance with the positions of valves which control the operation of the tool. These will be explained in connection with Figure 1l, and for the present it is suiicient to understand that the port 50 serves as an inlet port when Working fluid under pressure is supplied to the tool to move the piston 40 upwardly in the cylinder 34 for each grommet-setting operation of the tool. The port S0 serves as an exhaust port when working fluid is withdrawn from the cylinder.

There is a cylinder head 58 screwed into threads 59 in the upper end of the cylinder 34. The space between the head 5S and the piston 40 is lled with air. This air expands to push the piston downwardly when suction is applied to the other side of the piston. A handle 62 is attached to the cylinder 34 by cap screws 64 passing through the handle 62 and threaded into blocks 66 which are secured to the outside of the cylinder 34 by welding 67.

The piston 40 has a very limited stroke since the only purpose of the hydraulic power is to apply the actual setting pressure for the grommet; and the clamping plates are moved into position by hand operation of the grommet tool, this being an easy and rapid operation. In actual practice, a stroke of live-eighths of an inch has been found to be sucient with clamping plates that operate on grommets of approximately four inches in diameter. These figures are given merely by way of illustration.

When the lower clamping plate 10 is to be inserted through the hole in which the grommet is to be set, it is necessary to move the upper clamping plate 11 away from the lower clamping plate for a substantial distance so that the upper clamping plate will not strike against the wall of the duct when the grommet tool is tipped at a substantial angle for pressing the lower clamping plate through the opening. This clearance; between. the clamping plates and 11 is obtained by telescoping the sleeve into the body portion 30. A handle 70 is provided for the purpose.

The handle 70 is connected to the sleeve 20` by welding 72. A similar handle may extendl from the opposite side of the sleeve 20, but in the preferred construction there is merely a stud 74 extending from the sleeve 20 on the side opposite the handle 70. This stud 74 is attached to the sleeve 20 by welding 72. The handle 70 and the stud 74 extend into grooves in the side wall of the body portion 30. Figure l shows a slot 76 for the handle 70. It will be understood that the slot for the stud 74 is of similar construction on the other side of the tool.

The slot 76 has a substantial longitudinal extent, but at its lower end it has an angularly extending portion 77 which permits the handle 70 to be moved angularly and this turns the sleeve 20 about the longitudinal axis of the spindle 16. The lower side of this angularly extending portion 77 is formed by a ring 78 welded to the lower end of the body portion 30. There is a depression 79 toward the end of the angularly extending portion 77 of the slot 76. When the handle 70 is in the depression 79, the handle 70 can not move along the portion 77 of the slot unless the sleeve 20 first moves downwardly. This construction comprises a bayonet-type lock for preventing longitudinal` movement of the sleeve 20 with respect to the body portion of the tool. It is representative of means for locking the sleeve 20 against longitudinal movement after the sleeve has been moved downwardly to bring the upper clamping plate 11 into position close to the lower clamping plate 10 preparatory to the application of hydraulic power for moving the plates 10 and 11 toward one another in the final setting of the grommet.

There is an axially extending portion 80 at the upper end of the slot 6 for holding the sleeve 20 in its retracted position during the time when the tool is being initially inserted into the opening through the wall in which the grommet is to be set. This makes it unnecessary for the operator to hold the handle 70 when initially placing the tool in position.

Figures 5-8 show the construction of the auxiliary clamping plate 12 and the lower clamping plate 10 with which this auxiliary plate co-operates. In order to pass through an opening having a diameter less than that of the clamping plate 10, this clamping plate has portions of its sides cut away along surfaces 85, but in the final setting of the grommet, it is necessary to have a continuous clamping surface around the entire circumference of the lower clamping plate.

In order to provide such a continuous surface, the clamping plate 10 has a transversely extending depression 88 into which the auxiliary clamping plate 12 ts, as shown in dotted lines in Figures 7 and 8. When the lower end of the tool is being initially inserted through the opening in which the grommet is to be set, the auxiliary plate 12 is turned into position to bring its flat sides 89 substantially parallel with the at sides 85 of the lower clamping plate 10. After the plates 10 and 12 have passed through the opening, the auxiliary plate 12 is first turned angularly into alignment with the depression 88 and is then moved longitudinally into the depression 88 to form with the lower plate 10 a composite clamping plate having a iiush surface confronting that of the upper clamping plate.

To prevent relative rotation of the clamping plates 10, 11 and 12 with respect to one another, there is a stud 90 extending upwardly from the plate 12, and this stud extends into a socket 92 opening through the upper clamping plate 11 when the clamping plates are brought t0- gether preparatory to the application of power to the plates.

Figure 11 shows a motor 96 which drives a pump 97 for supplying working fluid, preferably oil, through a conduit 98 to the cylinder 34 of the grommet tool. There are valve means 100 commanding the cylinder port; and these valve means are operated by a knob 102 for selectively putting the port fitting 55 into communication with either the pressure conduit 98 or a suction conduit 105 leading to the other side of the pump 97. Thus in one position of the knob 102, the valve means supplies working uid under pressure to the cylinder 34; and in another position of the knob 102, the valve means shuts off the working fluid from the conduit 98 to the cylinder and puts the suction conduit 105 in communicaion with the port fitting 55 of the cylinder.

By manipulating the knob 102, the operator of the tool can Vapply and shut off the power at any time. Various kinds of valve means can be used for the purpose. The working iiuid can be supplied by means other than those illustrated, and different kinds of working fiuid can be used.

The preferred embodiment of the invention has been illustrated and described, but changes and modifications can be made and some features can be used in different combinations without departing from the invention as dened in the claims.

What is claimed is:

1. A grommet tool comprising a lower clamping plate,` a spindle to which the lower clamping plate is connected, an upper clamping plate, a sleeve surrounding the spindle and to which the upper clamping plate is secured, a hollow body portion through which the spindle and sleeve extend for at least a portion of their length and into which the sleeve is movable with a telescoping movement, means for locking the sleeve against telescoping movement when the sleeve is in an extended position which locates the clamping plates close together, and power means that moves the spindle longitudinally with respect to the hollow body portion in a direction to move the clamping plates together.

2. The grommet tool described in claim l, and in which the lower clamping plate has its sides cut away to reduce the width for passing through a hole of smaller diameter than the diameter of the clamping plate, and an auxiliary clamping plate of substantially the same diameter as the lower clamping plate and which also has portions of its sides cut away from passing through the opening, the auxiliary clamping plate being rotatable and axially movable into position to supplement the extent of the lower clamping plate by providing sections that complete the circumference of the lower clamping plate, and in which the means for locking the sleeve against telescoping movement includes a handle extending from the sleeve through a slot in the body portion of the tool, the slot including a bayonet lock section through which the handle passes when the sleeve is moved angularly about the longitudinal axis of the spindle.

3. A power-operated grommet tool comprising lower and upper clamping plates, a spindle to which the lower clamping plate is connected, a sleeve surrounding the spindle and to which the upper clamping plate is connected, a hollow body portion through which the spindle sleeve extends, the sleeve being movable longitudinally with a telescoping movement into and out of the hollow body portion, means for locking the sleeve in an extended position which locates the clamping plates close together, a cylinder at the upper end of the body portion, a piston in the cylinder secured to the upper end of the spindle which serves as a piston rod and means for supplying working fluid to the cylinder to move the piston in a direction to draw the clamping plates together.

4. A hydraulic grommet tool comprising upper and lower clamping plates, a piston rod connected to the lower clamping plate, a sleeve surrounding the. piston rod for at least the lower portion of its length and to which the upper clamping plate is secured, a hollow body portion into which both the piston rod and the sleeve extend, at least the upper portion of the sleeve being movable lengthwise in the body portion of the tool with a telescoping movement, a slot through the wall of the hollow body portion and extending lengthwise and then axially for a limited distance, a handle extending from the sleeve through the slot and forming with the axially extending portion of the slot a bayonet-type lock for preventing movement of the sleeve lengthwise of the body portion, a bearing in the upper end of the body portion and through which the piston rod extends, packing at said bearing around the piston rod, a cylinder at the upper end of the hollow body portion, a piston in the cylinder secured to the piston rod and located above a port opening through the side of the cylinder, and valve means commanding the port and movable into diierent positions to constitute the port an inlet or exhaust passage for working uid.

5. The hydraulic grommet tool described in claim 4 and in which the lower clamping plate has cut away sides for passing through an opening of reduced diameter and an auxiliary clamping plate with cut away sides but having a portion that lls in the cut away portions of the lower clamping plate when the auxiliary clamping plate is moved angularly and then longitudinally into a nesting relation with the lower clamping plate, means for preventing rotation of the auxiliary clamping plate when the upper and lower clamping plates are brought close together, said means comprising a stud and a socket, one of which is on the auxiliary clamping plate and the other of which is on the upper clamping plate, and in which the cylinder is a dierent piece from the hollow body portion and secured to the upper end of the hollow body portion by a screw thread.

References Cited in the le of this patent UNITED STATFS PATENTS 

